1. Field of the Invention
This invention relates to a printing method and an ink jet printer which are capable of printing on a printing medium by using an ink jet head, as well as a tape cartridge for use with the ink jet printer.
2. Prior Art
FIG. 15 shows a conventional printing method using an ink jet head. As shown in the figure, in the conventional printing method, an ink jet head H installed on a carriage is caused to reciprocate (for main scanning), and in synchronism with this reciprocation of the ink jet head H, a printing paper (printing medium) P is intermittently fed (for sub scanning) in a direction orthogonal to the direction of reciprocation of the ink jet head H, whereby printing is carried out.
As described above, in the conventional printing method, in order to increase printing speed, it is required to cause the ink jet head to reciprocate at an increased speed and with higher accuracy. In other words, the ink jet head which is relatively heavy in weight is required to be moved at a higher speed, and hence it is necessary to use a motor having a higher output power as a drive source. This results in increased power consumption. Further, since the ink jet head is moved at a high speed, fixed regions for acceleration and deceleration are required when the ink jet head undergoes transition from a standing state to a state moving at a constant speed, and transition from the latter to the former, which make it necessary to secure spaces for acceleration and deceleration of the ink jet head.
It is an object of the invention to provide a printing method and an ink jet printer which are capable of attaining the energy saving and reduced installation space as well as implementing high speed printing, and a tape cartridge for use with the ink jet printer.
To attain the above object, according to a first aspect of the invention, there is provided a method of sequentially printing on a printing medium having a printing area whose width is sufficiently larger than a length of nozzle arrays of a print head, along a width of the printing medium, by the nozzle arrays extending in a direction of the width of the printing medium.
The method according to the first aspect of the invention is characterized in that the printing on the printing medium is carried out while feeding the printing medium such that the printing medium is reciprocatingly moved, and at the same time intermittently moving the print head facing the printing medium in the direction of the width of the printing medium, the direction being orthogonal to a direction of feed of the printing medium.
According to this method, the printing medium is caused to reciprocate, and the print head is intermittently moved. That is, by setting the direction of reciprocation of the printing medium to the direction of main scanning, and the direction of intermittent movement of the print head to the direction of sub scanning, printing is sequentially carried out in the direction of the width of the printing area, so that the printing speed mainly depends on the reciprocating speed of the printing medium. The printing medium is lighter in weight and more flexible than the print head, whereby it is possible to save power consumption and shorten acceleration/deceleration distances required in the reciprocating motion, thereby attaining the saving of energy and printing space. Further, even if a simple construction (using rollers, for instance) is employed, it is possible to cause the printing medium to reciprocate at a high speed.
Preferably, the printing by using the print head is carried out not only when the printing medium is moved forward but also when the printing medium is moved rearward.
According to this preferred embodiment, it is possible to prevent a wasteful motion of the printing medium, thereby causing the same to reciprocate efficiently.
Preferably, the print head is caused to reciprocate over the printing area, and the printing is carried out not only when the print head is moved forward but also when the print head is moved rearward.
According to this preferred embodiment, it is possible to prevent a wasteful motion of the printing medium which is relatively heavy in weight, thereby moving the same efficiently.
Preferably, the printing medium is a printing tape which is stored in a form of a roll and rolled out for the printing.
According to this preferred embodiment, especially when a printing tape having a small width is used, the whole distance over which the print head is intermittently moved can be reduced, and by increasing the speed of the reciprocation of the printing tape while providing means for preventing jamming of the tape, it is possible to increase the printing speed with ease.
To attain the above object, according to a second aspect of the invention, there is provided an ink jet printer comprising:
a printing medium feed mechanism for feeding a printing medium having a printing area upon which printing is carried out, such that the recording medium is reciprocatingly moved;
a print head having nozzle arrays extending in a direction of a width of the printing medium, and being brought to the printing medium whose width is sufficiently larger than a length of the nozzle arrays, for sequentially printing thereon along the width of the printing medium, by the nozzle arrays; and
a head-moving mechanism for intermittently moving the print head in the direction of the width of the printing medium, the direction being orthogonal to a direction of feed of the printing medium,
wherein the printing is carried out by causing the printing medium to be reciprocatingly moved and at the same time causing the print head to be intermittently moved.
According to this ink jet printer, the recording medium is caused to reciprocate by the recording medium feed mechanism, and the print head is driven (for ejecting ink droplets) while being intermittently moved by the head-moving mechanism, whereby printing on the printing tape is carried out as desired. That is, by setting the direction of reciprocation of the printing medium to the direction of main scanning, and the direction of intermittent movement of the print head to the direction of sub scanning, printing is sequentially carried out in the direction of the width of the printing area, so that the printing speed mainly depends on the reciprocating speed of the printing medium. The printing medium is lighter in weight and more flexible than the print head, whereby it is possible to save power consumption and shorten acceleration/deceleration distances required in the reciprocating motion, thereby attaining the saving of energy and printing space. Further, even if a simple construction (using rollers, for instance) is employed, it is possible to cause the printing medium to reciprocate at a high speed.
Preferably, the printing medium feed mechanism includes forward feed roller means and rearward feed roller means arranged at respective downstream and upstream locations in the direction of feed of the printing medium with respect to the print head, and the forward feed roller means is configured such that the forward feed roller means rotates slightly faster than the rearward feed roller means, and is permitted to perform slip rotation when the printing medium is moved forward, and at the same time to perform free rotation when the printing medium is moved rearward.
According to this preferred embodiment, the distance over which the printing medium reciprocates and the speed at which the same moves for reciprocation is controlled by the rearward feed roller means. When the printing medium is moved forward, the forward feed roller means cooperates with the rearward feed roller means to feed the printing medium forward, and performs slight slip rotation for giving a constant tension to the printing medium. On the other hand, when the printing medium is moved rearward, the forward feed roller means rotates freely while the rearward feed roller means rotates reversely. This enables excellent printing operation and smooth reciprocation of the printing medium.
More preferably, the rearward feed roller means includes a drive roller and a driven roller opposed to each other with the printing medium positioned therebetween, and out of the drive roller and the driven roller, one roller positioned on a recording surface side of the printing medium has a pair of roller bodies which are located outside the printing area, and brought into direct contact with the printing medium.
According to this preferred embodiment, in the rearward feed roller means having a drive roller and a driven roller for feeding the printing medium such that the recording medium is reciprocatingly moved, one of the rollers positioned on the recording surface side of the printing medium has a pair of roller bodies which are located outside the printing area. Therefore, the pair of roller bodies are not brought into contact with a printed portion of the printing medium when the printing medium is fed such that it is reciprocatingly moved. That is, the rearward feed roller means for causing the printing medium to reciprocate is prevented from being brought into contact with a portion having ink droplets ejected thereon, of the printing medium. This makes it possible to prevent the rearward feed roller means from being stained by ink, and at the same time prevent ink from being attached to the printing medium via the rearward feed roller means. Further, there is no need to reduce the printing speed in view of drying of ink.
Further preferably, the ink jet printer further includes a longitudinally-cutting cutter for cutting the printing medium for which the printing has been completed, at a location inward of a portion of the printing medium with which the pair of roller bodies are brought into rolling contact, along the direction of feed of the printing medium.
According to this preferred embodiment, a printing medium having a predetermined width can be used for producing a printing medium having a printed portion and a desired width. This makes it unnecessary to provide an ink jet printer which is capable of receiving a plurality of kinds of printing mediums having difference widths. Further, after the printing medium is printed with predetermined background colors, if the printing medium is cut to have a slightly smaller width than the printing width, it is possible to obtain a cut-off strip of the printing medium having a background painted all over.
Still more preferably, the longitudinally-cutting cutter has a pair of cutter blades, the pair of cutter blades being constructed such that a distance therebetween can be adjusted.
According to this preferred embodiment, each printing medium can be freely cut to have a desired width. Further, it is possible to automatically set a cutting width relative to a printing width by taking margins into account.
Still more preferably, the printing medium has an adhesive layer coated on a reverse side surface opposite to the recording surface and a peel-off paper provided on the adhesive layer, wherein the longitudinally-cutting cutter performs half-cutting of the printing medium such that the peel-off paper is left uncut.
According to this preferred embodiment, a printed portion of the printing medium, which has the same width as its original width, is sent out of the ink jet printer in a manner held by the peel-off paper. The printed portion cut to have a desired width is peeled off the peel-off paper. This makes it easy to deal with a printed portion of the printing medium.
Preferably, the print head is installed on a carriage, and the head-moving mechanism has a screw shaft in screw engagement with the carriage, a guide shaft in slidable engagement with the carriage, and a motor for rotating the screw shaft.
According to this preferred embodiment, the motor as a drive source and a screw mechanism formed between the screw shaft and an engagement portion of the carriage are used to intermittently move the print head, so that the head-moving mechanism having a compact and simple construction can intermittently move the print head with accuracy.
Preferably, the ink jet printer further includes a buffer for receiving a returned portion of the printing medium when the printing medium is moved rearward.
According to this preferred embodiment, it is possible to suitably protect the returned portion of the printing medium, and at the same time effectively prevent the returned portion from causing jamming or the like inconveniences.
Preferably, the printing medium is a printing tape which is stored in a form of a roll and rolled out for the printing.
According to this preferred embodiment, especially when a printing tape having a small width is used, the whole distance over which the print head is intermittently moved can be reduced, and by increasing the speed of the reciprocation of the printing tape while providing means for preventing jamming of the tape, it is possible to increase the printing speed with ease.
Preferably, the ink jet printer further includes a tape cartridge containing the printing tape, the tape cartridge being removably mounted in the ink jet printer.
According to this preferred embodiment, the printing tape in the form of a roll can be easily handled.
To attain the above object, according to a third aspect of the invention, there is provided a tape cartridge removably mounted in an ink jet printer that carries out printing by feeding a printing tape such that the printing tape is reciprocatingly moved, and at the same time by intermittently moving a print head facing the printing tape in a direction orthogonal to a direction of reciprocation of the printing tape,
the tape cartridge comprising a cartridge casing accommodating the printing tape in a form of a roll.
Preferably, the cartridge casing is formed with an opening for allowing a returned portion of the printing tape to escape from within the cartridge casing when the printing tape is moved rearward.
According to this preferred embodiment, the printing tape is fed such that it is reciprocatingly moved, and at the same time the print head is intermittently moved, whereby it is possible to carry out printing by an ink jet printing method in which the printing tape is moved for main scanning, and the print head is moved for sub scanning. Further, the printing tape is contained in the cartridge casing to facilitate handling of the printing tape, and the cartridge casing is formed with an opening for allowing a portion of the printing tape being printed and returned by a rearward movement of the printing tape to be suitably escape out of the cartridge casing. This makes it unnecessary to take up the returned portion of the printing tape within the cartridge casing, so that the construction of a tape core or the like can be simplified, and the jamming of the printing tape in the cartridge casing can be prevented.
Preferably, the cartridge casing is provided with a guide member for guiding the returned portion of the printing tape out of the cartridge casing through the opening.
According to this preferred embodiment, it is possible to smoothly guide the returned portion of the printing tape out of the cartridge casing through the opening, thereby inhibiting the returned portion from returning toward the tape core.
Preferably, the printing tape is fed such that the printing tape is reciprocatingly moved by tape feed roller means having a drive roller and a driven roller, and the cartridge casing contains the driven roller.
According to this preferred embodiment, when the tape cartridge itself is mounted in the ink jet printer, the printing tape can be automatically held between the drive roller and the driven roller, thereby enabling and maintaining a feed wait state of the printing tape.
More preferably, the tape feed roller means comprises forward feed roller means and rearward feed roller means arranged at respective downstream and upstream locations in a direction of feed of the printing tape with respect to the print head, the forward feed roller means and the rearward feed roller means each comprising the drive roller and the driven roller arranged in a manner opposed to each other with the printing tape sandwiched therebetween.
The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.